"There is a flow to history and culture. This flow is rooted and has its wellspring in the thoughts of people. People are unique in the inner life of the mind – what they are in their thought world determines how they act. This is true of their value systems and it is true of their creativity. It is true of their corporate actions, such as political decisions, and it is true of their personal lives. The results of their thought world flow through their fingers or from their tongues into the external world. This is true of Michelangelo’s chisel, and it is true of a dictator’s sword.

People have presuppositions, and they will live more consistently on the basis of these presuppositions than even they themselves may realize. By presuppositions we mean the basic way an individual looks at life, his basic world view, the grid through which he sees the world. Presuppositions rest upon that which a person considers to be the truth of what exists. People's presuppositions lay a grid for all they bring forth into the external world. Their presuppositions also provide the basis for their values and therefore the basis for their decisions.

'As a man thinketh, so is he,’ is really most profound. An individual is not just the product of the forces around him. He has a mind, an inner world. Then, having thought a person can bring forth actions into the external world and thus influence it. People are apt to look at the outer theatre of action, forgetting the actor who "lives in the mind" and who therefore is the true actor in the external world. The inner thought world determines the outward action.

Most people catch their presuppositions from their family and surrounding society the way a child catches measles. But people with more understanding realise that their presuppositions should be chosen after a careful consideration of what world view is true. When all is done, when all the alternatives have been explored, "not many men are in the room" - that is, although world views have many variations, there are not many basic world views or basic presuppositions. These basic options will become obvious as we look at the flow of the past."

Schaeffer, Francis A. (2005). How Should We Then Live: The Rise and Decline of Western Thought and Culture. Illinois, USA: Crossway Books. (pp. 19-20)